Namibia plans to introduce Kiswahili in its curriculum by 2021, but opposition parties question the cost of the move.
According to reports circulating in media, political parties have questioned the financial implications of the government's plan.
Sanet Steenkamp, Namibia's executive director for education, revealed plans to endorse Kiswahili as an optional language by next year following discussions with Tanzania President John Magufuli which started in July last year during an official visit.
"As a Cabinet we will set up the ground work this year and also work with the National Institute for Education on ways to pilot teaching of the language in national schools by 2021," said Ms Steenkamp.
According to a statement issued by Michael Skini, secretary-general of the United Democratic Front Youth League, the introduction of Kiswahili in schools would be too costly even though Tanzania pledged to provide teachers and materials.
"We are told Kiswahili teachers and learning materials would be provided by the Tanzania government, but for how long?" said Mr Skini.
President Magufuli promising support for adoption of Kisawihili in Namibian schools in a bid to unlock barriers to trade and foster better relations between the two countries.
Maximilliant Katjimune, a spokesperson of the national opposition party, Popular Democratic Movement said rejecting teaching of Kiswahili in schools should not be viewed as being un-African, instead the country should carry out a cost analysis because there are more immediate challenges facing the country's education sector.
South Africa recently adopted teaching of Kiswahili and identified 90 schools across the country to start the pilot phase.
Around five million people speak Kiswahili as a first language, while a 135 million people speak it as a second language.
It is spoken in many countries in Africa, United Arab Emirates and the USA.