The National Government and its Maori Party partners presented a united face when Prime Minister John Key visited Ratana Pa this afternoon.

At the Ratana religious movement's annual celebrations near Whanganui today, Mr Key and his National Party colleagues unexpectedly walked on to the marae with Maori Party MPs in a show of unity he later said he had not expected.

"Obviously I was delighted to walk on alongside the Maori Party and obviously it's been a strong relationship in the two years we've been in Government," said Mr Key.

That show of unity comes as National's relationship with the Maori Party has shown signs of strain as rogue MP Hone Harawira last week again broke ranks to criticise government policies and his own party's direction.

"There will always be differences - that's the natre of coalition government and it's the nature of independent parties," said Mr Key. "But at the end of the day, I think as a unified team we've made great progress for New Zealand and I've enjoyed the relationship we've had with the Maori Party."

Mr Key began his address to the gathering with a two-minute speech in te reo Maori. He said he had been practising and planned to give a more substantial address in te reo at Waitangi Day celebrations in two weeks' time.

While Labour leader Phil Goff earlier in the day won an indication from Ratana elders that the church was now looking to reconnect with Labour, Mr Key took heart from the strength of his relationship with the Maori Party and said he believed by working for a brighter future for all New Zealanders, he hoped to win more support from Maori voters over time.

In a comment clearly aimed at Mr Harawira, Mr Key said: "I say to those critics, what can you achieve from opposition? And the answer is nothing.

"You achieve things when you are part of the solution, not when you are solely carping on about problems."

Speaking to media after his official address, Mr Key said: "If you look back on the last two years and ask yourself would many of the achievements have happened without the Maori Party's relationship in Government, I think the answer to that is no and I think Hone Harawira knows that."