The quartet includes three cabinet ministers, the Deputy Prime Minister Poasi Tei, Finance Minister Tatafu Moeaki, and Sangster Saulala, along with the former Prime Minister Pohiva Tu'i'onetoa.
They lost their seats when accusations of bribery of voters ahead of last year's election were proven.
RNZ Pacific's Tongan correspondent said, now, with all the ministers able to stay, the Tongan Parliament, which has been deferred twice in the past two weeks, is likely to sit next week.
Kalafi Moala said getting the Budget passed is the critical thing for the government.
