Speaker Lockwood Smith risks a rebellion at the swearing-in of the new Parliament later this year after he ejected Mana leader Hone Harawira for paying allegiance to the Treaty of Waitangi instead of the formal oath to the Queen.

Some MPs - in particular the Green Party and Maori members - have objected to the Speaker's handling of Mr Harawira, saying he should have been given a second chance, as happened in the past.

There is also concern that Dr Smith's decision sets a precedent for the swearing-in of the new Parliament after November's election, which could result in protest oaths by some MPs who had previously delivered their own oath before being pulled up and told to take the version set down in law.

The Speaker would not comment yesterday on the issue, but told MPs it was against the law not to give the appropriate oath and voiced concern that it had become an increasing practice.

He said Mr Harawira had been warned about it beforehand.

In the past several MPs - including the Maori Party's and some in the Greens - have altered the oath to include the Treaty of Waitangi before being stopped and told to deliver the correct wording stipulated by law.

Green MP Kevin Hague said if he was re-elected he had every intention of doing so again, but would have an "ethical dilemma" if the Speaker laid down the hard word beforehand.

"For an oath to be meaningful it needs to be meaningful to the person giving the oath. What MPs in New Zealand should be swearing allegiance to is to New Zealand, and it is appropriate to include allegiance to the Treaty in that."

Maori Party co-leader Tariana Turia said she had now written to the Speaker to seek advice on how to alter the oath or provide for an alternative which included the Treaty.

Any such move would require a law change and is something Mrs Turia has pushed for since 1999 when she entered Parliament with Labour.

After the Te Tai Hauauru byelection in 2004, Mrs Turia was the first MP to give her oath only in te reo Maori. A law change allowed it.

Before that, MPs had to give an English oath also. Yesterday, she said while it was a matter that could be considered as part of a wider constitutional review - led by her fellow co-leader Pita Sharples and Deputy Prime Minister Bill English - she was also looking at other avenues.

These included reintroducing an amendment the Maori Party had tried to have included in changes to the Oaths and Declarations Act in 2006.

Although Mr Harawira will not be formally sworn in to Parliament until the next sitting week on August 2, he will still receive his MP's pay and entitlements because by law he became an MP the day after the election results were confirmed.

However, he cannot vote or take part in debates in the House until he is sworn in.

Mr Harawira said the delay had little practical effect because the House was in recess until August 2 anyway.

Maori and the oath
1996

Maori MPs push to give the oath in Maori. They are allowed, but must also give it in English. Tariana Turia includes allegiance to the Treaty of Waitangi and the Maori Queen in her Maori version.

1999

Mrs Turia pledges allegiance to the Treaty of Waitangi and Queen Elizabeth. Is told it is unacceptable. Prime Minister Helen Clark says the Government might consider changing the oath in the future, but not "on the spot".

2004

Law is changed to allow MPs to give oath in Maori or English. Mrs Turia is the first MP to give a Maori-only version of the oath after winning the Te Tai Hauauru byelection.

2005

All four Maori Party MPs (Pita Sharples, Hone Harawira, Te Ururoa Flavell and Mrs Turia) mention the Treaty of Waitangi in their oaths and are made to repeat them without it. Later, Mrs Turia and Mr Harawira say the oath should be changed.

2008

Green MPs Catherine Delahunty and Kevin Hague insert the Treaty of Waitangi into their oaths. Told to repeat them correctly.