The event was (at the time of going to print on Wednesday, February 15) set to conclude on Wednesday afternoon.
On Tuesday, Blainey fired a sublime seven-under-par 65, while Lawrence impressed with a flawless 66.
The pair shared the lead at nine under 135 and started the final round with a one-shot advantage over Englishman Martin Dewhurst, who rose to third with successive rounds of 68.
They were two shots clear of joint overnight leader Wayne Stroebel, Matt Bright, Paul Boshoff and Coert Groenewald.
Second round scores at the close of play on Tuesday were:
• 135 – Gregg Blainey (ENG) 70 65, Thriston Lawrence 69 66;
• 136 – Martin Dewhurst (ENG) 68 68;
• 137 – Wayne Stroebel 67 70, Matt Bright 69 68, Paul Boshoff 70 67, Coert Groenewald 70 67;
• 139 – Andi Dill 70 69, Jonathan Waschefort 69 70, Dean O’Riley 72 67, Christopher Van der Merwe AMA 71 68, Jacques De Villiers 72 67, Philip Geerts AMA (ITA) 69 70;
• 140 – Leon Visser AMA 67 73, Alrich Labuschagne 70 70;
• 141 – Quintin Crause 69 72, Justin Turner 72 69, Paul De Beer 69 72, David Ashley (ENG) 70 71, Joubert Van Eeden 74 67, JP Rousseau AMA 70 71, Estiaan Conradie 76 65, Kyle Barker 73 68;
• 142 – Michael Dreyer 69 73, Clinton Grobler 71 71, Vaughn Van Deventer AMA 74 68, Gilson Filho (BRA) 73 69, Juan Langeveld 71 71;
• 143 – Shaun van Tonder 71 72, Christian Basson AMA 74 69, Matthew Spacey 75 68, Dylan Docherty 74 69, Duane Keun 75 68;
• 144 – CJ Levey 74 70, Michael Kok AMA 74 70, Aneel Kallan AMA 72 72, Bradley Van Biljon AMA 70 74, Shalan Govender 75 69, Ruan Conradie 77 67, Dwayne Coetzee 74 70;
• 145 – Ruhan Van Dijk AMA 75 70, Divan Marais 69 76, Thabi Ngcobo 77 68, Mpho Mafishe 71 74, Jadrick Fourie AMA 72 73, Craigen Clough AMA 70 75;
• 146 – Richard O’Donovan (IRE) 74 72, Chase Paton AMA 74 72, Stephan Du Toit AMA 73 73, Steven Jacobs AMA 75 71, Jabulane Mabilane 73 73, Ruan Korb AMA 72 74, WM Coetzee AMA 75 71, Norman Beggs 75 71;
• 147 – Fanie Wolmarans AMA 73 74, Stephan De Beer 77 70, John McClean (NIR) 76 71, Michael Schutz 78 69, Gary Daoust (BEL) 73 74, Terence Boardman 74 73;
• 148 – Reinard Vermeulen AMA 78 70, Arno Pretorius AMA 76 72, Shaun Barrett AMA 76 72, Bryce Myburgh 77 71, Niel Theron AMA 80 68.