JOHANNESBURG - As the Congress of South African Trade Unions (Cosatu) Special National Congress prepares to get underway, there have been claims that the delegations sent by unions don't represent their workers' views.

The congress kicks off today after two years of infighting between affiliates at Cosatu's highest decision making structures.

Security is tight at the Gallagher Convention Centre amid concerns of disruptions by some union leaders.

Divisions between unions are already visible through the different songs sung.

More than 2,500 delegates are attending the meeting called to discuss unity and cohesion.

Security has been beefed up due to what Cosatu's leadership says is a plan to disrupt the congress by the National Metalworkers of South Africa (Numsa).

#COSATU After failing to negotiate a truce between rival factions, SG Gwede Mantashe is not at ANC table. GW pic.twitter.com/NfuCPMFl0Q

— EWN Reporter (@ewnreporter) July 13, 2015

Delegates attending this congress are being searched and screened before entering the conference hall with security visible throughout the convention centre.

They include members from the police's Public Order Unit, Johannesburg Metropolitan Police Department, Cosatu security and other officials who refused to divulge who they have been hired by.

Inside the main hall some unions appear divided according to different provinces.

They've been singing songs calling for change while others sing praises for Cosatu's president and the African National Congress.

Leaders of the rebel unions claim the meeting to select the delegation at South African Transport and Allied Workers Union (Satawu) was disrupted by unhappy workers last night.

Picture: Govan Whittles.

The Food and Allied Workers Union's (Fawu) Katishi Masemola said leaders are trying to micromanage their members.

"We are not surprised really because some may be trying to manage the outcome of this congress and that's why they manipulate their delegation."

Labour analyst Terry Bell said the selection process has not been transparent.

"It depends on how the delegates have been selected; there has been a lot of fighting about that. Satawu is the union I believe has had physical battles about who should be at this conference."

The congress is due to start shortly.

#COSATU The main plenary is filling up. Only a few more unions need to submit credentials before congress starts. GW pic.twitter.com/tJOOaejoV7

• EWN Reporter (@ewnreporter) July 13, 2015

#COSATU FAWU says it will raise its issues constructively and wants the congress to be robust. GW

• EWN Reporter (@ewnreporter) July 13, 2015

#COSATU The selection of delegations to attend this congress has been marred by controversy. Some NEHAWU & SATAWU delegates are unhappy. GW

• EWN Reporter (@ewnreporter) July 13, 2015

#COSATU Union delegates arriving at Gallagher conference center in Midrand. SAPS members guarding entrance. GW pic.twitter.com/ibcGyPNAXM

• EWN Reporter (@ewnreporter) July 13, 2015

#COSATU Welcome to COSATU's special national congress, called to discuss unity & cohesion. Govan Whittles reporting. pic.twitter.com/hmUids27td

• EWN Reporter (@ewnreporter) July 13, 2015