Kiribati is becoming a one-party state while the delivery of basic services is near collapse, according to the opposition leader in the last parliament, Tessie Lambourne.

She said the people of Kiribati are being denied their right to have a Beretitenti, or President, of their choosing.

Kiribati is preparing for a presidential election next month, but all four candidates chosen by parliament, are from the dominant party in the new parliament, the Tobwaan Kiribati Party (TKP).

Lambourne, who was seen as the only credible alternative to caretaker Beretitenti Taneti Maamau - was blocked by the Maneaba, or parliament, from contesting the presidential election.

She was one of six nominees who sought a place on the ballot for the election - four from the TKP and the sixth a newly elected independent MP.

There can only be a maximum of four candidates for president.

The TKP used its significant majority in the Maneaba to ensure that only its nominees would be selected.

They are Maamau, Bauntaake Beia, Riteta Iorome, and Kaotitaake Kokoria.

Lambourne said voters are not being given a genuine choice because the other three TKP members will be encouraging support for Maamau.

She said this is not how a democracy is supposed to work.

"Over the past eight years under the TKP we have seen Kiribati rapidly decline into authoritarianism and isolationism.

"It seems that Kiribati is now a one-party state, and her people are suffering as a result."

Lambourne said basic services, such as health, education and utilities "have deteriorated to the point of near collapse and will not continue without the ongoing support of our development partners".

"Our institutions have been weakened. Accountability and transparency are virtually non-existent. This is a sad time for Kiribati and her people."

She said the Maneaba had decided who the next Beretitenti will be, not the people of Kiribati.

For the first time in the 45 years since independence, the people will not be able to choose a Beretitenti from among candidates offering different visions for the future of the nation, she said.

"It appears that the Beretitenti is afraid to have an honest contest of ideas and let the people of Kiribati have their say."

RNZ Pacific has contacted the Office of the Beretitenti for comment.