World Anti-Doping Agency (Wada) presidential candidate Linda Helleland has accused her rival of acting "in bad faith" after he called on her to step down as the organisation's vice-president.
In a written response to Polish sports minister Witold Banka - seen by the BBC - Helleland claims his suggestion "has the appearance of further political manipulation".
It is the latest twist in an increasingly acrimonious race to succeed Sir Craig Reedie as supremo of sport's global anti-doping watchdog.
Former athlete Banka had urged the Norwegian minister to leave her position as he claimed already holding an influential position at the organisation gives her an unfair advantage in the fight to land the role.
He also criticised Helleland's attendance at an anti-doping summit held at the White House in Washington DC, and suggested she had manipulated athletes' support for her advantage.
"I fully support good governance, and good governance promotes openness and transparency," Helleland wrote to Banka.
"To suggest otherwise is offensive.
"I am sure you are aware of the global outcry Wada is facing and for you to openly and publicly call for me to step down is in bad faith and has the appearance of further political manipulation and interference.
"Like you, I am entitled to attend any gathering I wish in the interest of clean sport," said Helleland.
"If Wada is to be a democratic organisation, the people that sit on the organisation's boards should be able to openly express their opinion on the best way forward for the organisation and not be sidelined, pressured or bullied into being silenced," she added.
In October, the chair of Wada's Athlete Committee said some of the organisation's most senior officials tried to "bully" her over her opposition to Russian reinstatement - a claim Wada denied.
Reformist candidate Helleland - who has received the formal backing of Norway's government - has similarly been a vocal critic of Wada and the International Olympic Committee (IOC) in the wake of the Russian doping scandal.
She voted against Wada's decision to reinstate Russian anti-adopting agency Rusada in September.
Too young to stand?
Meanwhile, a controversial suggestion by representatives of African governments that presidential candidates must be at least 45 years old is "quite likely" to be dropped, according to an official who helped draft proposed rules for the election.
Sergey Khrychikov, a senior bureaucrat at the Council of Europe - who works on behalf of government representatives at Wada - told the BBC he had "contributed to the preparation of the draft document on the process to identify a single public authorities' candidate".
However he denied being responsible for the proposal of an age restriction, which has been interpreted by some as an attempt to block Helleland from standing, as she is 41. The idea has been condemned by the Athletes for Clean Sport Group which has demanded increased representation at Wada.
"As correctly explained [by Wada] the document was finalised by the African Union public authority representatives and distributed by them," said Khrychikov.
The Ukrainian sits on a Rusada supervisory board.
The proposal could be raised at a meeting of Wada's Foundation Board in Baku on Thursday.
Wada presidents are elected by the 38-member body, consisting of an equal balance of representatives from sport and governments.
Meanwhile, Helleland has invited Reedie - with whom she has recently clashed - to a meeting in Oslo "to improve our work".
The African Union Council representatives did not respond when approached for comment.