The youth wing of Fiji's Social Democratic Liberal Party are against any move by its board to form a coalition with FijiFirst post-election.
Speaking to media in Suva on Sunday, leader Viliame Gavoka said the party had 14 days to consider its options.
"We are not in any hurry, we understand the importance of this, but we're not going to rush. We are going to do this properly but with urgency," he said.
RNZ Pacific has seen a copy of the letter in which the Sodelpa Youth Council expressed their "distaste" to the party's main decision-making board for "agreeing to consider" Prime Minister Frank Bainimarama's FijiFirst as a potential partner.
"We beg the executives to consider wisely and inclusively on the Party's move," the letter states.
"The people are our source of strength and therefore their voice is what we shall recognise," it adds.
It further states that although the party has differences with the People's Alliance leader Sitiveni Rabuka "he may be the only option we can take to work with" to put an end to "16 years of dictatorial leadership" under Bainimarama.
The youth arm believes the Sodelpa management's decision to consider proposals from FijiFirst shows the "desperation and compromised approach" the party is willing to take to form a government.
Sodelpa's management board - which is made up of over 40 members from 28 constituencies - is expected to meet on Monday morning local time to make a decision.