Pensioners in the Cook Islands say they will keep up the pressure on the Cook Islands government not to have their New Zealand-paid pensions back taxed.

The elderly have been taking to the streets in recent weeks to protest, and they say they'll do so until the government gives in.

Sally Round has been in Rarotonga.

The tax has been on the lawbooks for a while but not enforced until this year and that has many of those receiving the New Zealand pension incensed. The government says it has discovered about 260 Cook Islanders receive the pension and it wants them to start complying with the law and also pay two years worth of arrears ... about US$3,600 per person. One of the protestors, Teariki Simiona, does not see why the pensioners should pay any tax at all as he says they are not a big burden on the Cook Islands.

"TEARIKI SIMON: Some of the mamas and the papas here, they rely on that money to pay their airfares back and forward. Some of them here, they go back to New Zealand for a further check-up because they don't have the services here to do it."

The vice-president of Grey Power, Dennis Tunui, says it's the arrears that are the big problem with many who will struggle to pay the lump sum.

DENNIS TUNUI: We are in our mid-seventies, eighties, nineties. That's the ones they are hitting. We are telling them we can't handle this. We are prepared to be taxed like all tax should be. This is new, backdating on vulnerable people. It's not right.

Mr Tunui says the government is being inconsistent and unfair in its demands.

DENNIS TUNUI: It's scaring some of them. Two, three letters telling them to come and fill in a form while some are not getting anything at all. That's one reason we brought all the letters back to tell them 'Get yourself organised, be consistent'. It's becoming a joke!

The pensioners marched on government offices in Avarua with their complaints and were met on the doorstep by the Finance Secretary Richard Neves. Mr Neves says the government is just enforcing the rule of law and it's only fair the pensioners should pay tax. He says some couples have been receiving US$25,000 tax-free, while young Cook Islanders earning half that amount are paying tax. But Mr Neves says if the elderly can demonstrate hardship they might be exempt.

RICHARD NEVES: Each individual's circumstances are quite different. They can be significantly different. And if they come up and see me, in genuine cases of hardship, no one's going to recover taxes. But we just can't do a blanket [exemption].

Dennis Tunui, says that's just a ruse to split the Grey Power movement and he's telling people not to be tricked. About 80 people marched again on Friday and presented their case to the Cook Islands Prime Minister Henry Puna. Mr Tunui says Grey Power will continue to chip away over the issue and he says he is sure the Prime Minister will eventually give in.