The Government has decided to back a bill increasing penalties for animal cruelty.

The decision followed a National Party caucus discussion this morning about adopting Tauranga MP Simon Bridges' member's bill to increase maximum sentences for animal cruelty offences from three to five years as a government bill.

Agriculture Minister David Carter issued a statement that he would introduce the Animal Welfare Amendment Bill 2010 into Parliament for referral to select committee.

"I will also be considering whether we can widen the scope of the bill to make the Animal Welfare Act work better," Mr Carter said.

"The adoption of this bill will complement a range of work that the Government already has under way in the animal welfare area. Increasing incidences of animal cruelty are horrifying many New Zealanders and the National Government wants to see stronger measures in place to deal with this issue."

Before caucus Justice Minister Simon Power said he supported the idea of increasing sentences for animal cruelty offences but was concerned that proportionality for crimes against people was kept.

"It is important that proportionality remains. And I will be making sure that's factored into any decisions."

He is reviewing Part 8 of the Crimes Act which covers offences against the person and is doing work on increasing sentences for offences against children.

Asked if some criminal sentences might be increased to preserve proportionality, Mr Power said: "If the bill goes to a select committee I am sure all of that will come out."

There have been recent high profile cases of cruelty to animals, including the slaughter of 33 dogs near Wellsford, north of Auckland, last week.

The Labour Party says it supports the bill in principle and the Greens are also in favour of it.

Green Party MP Sue Kedgley said yesterday the Government should also make cruel practices like keeping pigs in crates and chickens in battery cages illegal.

"We need to make certain that any legislation covers all forms of animal abuse, including institutional abuse such as keeping pigs and hens in cages for the duration of their lives - those practices are legal," she said.

Farmers also should be punished for individual cases of cruelty, she said.

There had been several cases of farmers starving cattle but escaping with fines or community sentences.

Very few cases of animal cruelty have resulted in prosecutions - about 1 per cent of cases - and only 3 per cent of that group get jail sentences.

National is holding an all-day caucus meeting today at Premier House, Mr Key's official residence.

MPs will be told about the Government's plans for the year and its thinking on issues like changes to the tax system.