Something suspicious is happening. The Prime Minister and Attorney-General insist their proposed new foreshore and seabed law will allow free public access, and accuse Dr Hugh Barr of the Coastal Coalition of telling untruths when he disagrees.

But when the Attorney-General says he will nevertheless propose amending the bill in order to make things 100 per cent clear, the Maori Party threatens to abandon its support for the bill, Hone Harawira calling Act's leader "a little fat redneck".

Why might Maori be angry, if things were only to be made clearer and nothing were actually to change?

I will be more charitable to John Key than he is to Dr Barr, but I have to accuse him of being misinformed. Dr Barr is right. In its present form National's bill can be interpreted to allow the public to be charged for access to any foreshore and seabed to which iwi, hapu or whanau have gained "customary marine title".

If Chris Finlayson is unaware of that possible interpretation then he is not as good a lawyer as he thinks he is. And it is most certainly the case that when Maori obtain customary title, they will be able to exclude the public from those parts of their new territory which they designate as "wahi tapu".

This will remain the case, for Mr Finlayson does not intend to amend this. On the matter of wahi tapu he is silent.

Mr Finlayson's argument on the first issue, as to why free public access will exist even after he has given Maori customary title (as he will be able to, after private negotiations with absolutely no public input or judicial review or appeal), is this.

Section 27 of his bill says every individual has the right of entry to the "common marine and coastal area", (the "cmca").

By section 60 any coast and sea to which Maori obtain title continues to be part of the cmca, to which, therefore, section 27 still applies. And by section 63 the only rights which the new title-holders have to the cmca are those listed, and the right to exclude the public or charge to admit them is nowhere mentioned.

That is true, but when is law straightforward? Arguments also run the other way. Under Labour's 2004 Foreshore and Seabed Act, Maori could claim something similar to customary marine title, called territorial customary rights, over an area, and might thereafter establish a reserve there. But section 40 of the act specifically declared that the reserve was held for the common use and benefit of the people of New Zealand, and also that no one was "entitled to charge or collect fees or other form of payment" from its users.

There is no equivalent of this in the new bill. The point is this: a well-established and sensible rule of statutory interpretation says that where one statute replaces another, and the new statute does not repeat a particular provision in the old one, then there is a presumption that that provision no longer applies.

Why was this particular provision left out? The answer must be, because Parliament no longer intended it to apply.

One statute forbids charging - its replacement is silent. What are we to conclude?

It is simply impossible to believe that the omission of an equivalent of section 40 from Mr Finlayson's bill was by accident. It must have been deliberate. Why?

Moreover, section 63 of the new bill says that the new title-holders may derive commercial benefit from exercising their rights. How might they?

Tourism is a very obvious possibility, but profit from tourism might be difficult if ordinary members of the public could not be excluded.

And although the right to exclude others (and, correspondingly, charge for permission) is nowhere specifically listed as one enjoyed by holders of customary marine title, it could be replied that the right to exclude others from one's property is so fundamental that it does not need to be mentioned at all.

The bill does, after all, describe customary marine title as "an interest in land".

At present, then, it is not clear that the bill would allow public access to newly acquired Maori title. That is a possible interpretation, but a court could also decide the opposite without doing any more violence to this badly drafted law. I cannot help but wonder if the phrasing was deliberately left unclear, and that Maori Party anger now is because it had been led to believe that charging was possible.

But all that aside, the bill is absolutely clear that when Maori claimants obtain their customary title, they will be able to designate areas as "wahi tapu", and the public may be wholly or partly excluded from these areas, or allowed entry only on conditions.

Section 77 specifically speaks of "prohibitions or restrictions on access".

No one can say what these areas will be. They need not be burial grounds, or the sites of battles - although why should it be forbidden to visit a battlefield? No, wahi tapu are merely "sacred" in any traditional, religious, ritual or mythical sense. That could be anywhere. There need be nothing there - the Historic Places Trust has already recognised one area as wahi tapu merely because it is mentioned in a song.

We simply cannot say where these areas are, or how large they will be, until after this bill becomes law, when we will undoubtedly receive some very unpleasant surprises.

It is quite certain that after it becomes law there will be restrictions or prohibitions on public access, and if the Prime Minister and Attorney-General say there will not be then they are at best ill-informed.

Ask them about wahi tapu.

David Round is a law lecturer at the University of Canterbury and author of Truth or Treaty? Commonsense Questions About the Treaty of Waitangi.